I have never found "X lines of code" to be impressive. Write clean code and polish it and make it readable. Who cares how long it is. Hackers brag about lines, not engineers.
It requires Silex, a micro-framework, not Symfony. Symfony is a much larger framework that isn't required. He just used two of its modular components, Request for HTTP request parsing, and Process for spawning subprocesses.
Silex is hardly a "micro framework", it's basically Symfony without the configuration files. So it's a LOT of code. I like it by the way, always hated the Spring like insanity of Symfony, but let's not pretend Silex + all Symfony libs the framework has to import are small.
The irony is that for this very project, Both Silex and Symfony\Process are completely redundant, especially with PHP bloated core APIs.
That's not correct. Silex replaces the Symfony DI (or service locator, if you will) component with something much simpler called Pimple. You can read the code within a few minutes.
The only other required libraries for Silex to function are the event dispatcher, routing (which you can swap out for something like nikic/FastRoute), and the request/response stuff. I'm not sure if you think that's a "lot" of code, but if you're rolling your own you'd probably end up using the HTTPFoundation stuff anyway.
People like to specialize and seek extremes of different metrics. Do you think that the demoscene is not impressive because they could do much more with more than 4k of code?
This comment is an example of the type of negativity that is unhelpful and creates the toxic atmosphere HN is renown for, and I believe you know that considering you posted with a throwaway.